Extended-reach wells completed without washpipe, saving 10 days and USD 10 million

Using ResFlow™ check-valve ICDs in the North Caspian enabled running stand-alone screens in five extended-reach wells without washpipe or coiled tubing for oil-based mud displacement and cleanup operations. The operator saved 2 days and USD 2 million per well.

Alternative to washpipe required in extended-reach wells with sand control

An operator was developing an oil field with openhole extended-reach wells that had measured depths up to 5 mi [8 km] and TVDs of approximately 0.9 mi [1.5 km]. A sandstone formation with a large gas cap necessitated sand screens with inflow control devices (ICDs) to minimize early gas breakthrough. Rotating the screens was key to reaching target depths in these wells, where openhole sections reached up to 3.1 mi [5 km]. To reduce torque friction and address shale instability, oil-based mud (OBM) was used during drilling and running in hole.

In the first six wells, the OBM was left in the open hole until the upper completion was run, and it was partially recovered during well lifting and production. Solids in the mixture of freshwater, crude oil, OBM, and brine damaged the pumps and other surface facilities, which consequently had to be refurbished after every well startup. Moreover, the incomplete cleanup prevented the toe intervals from producing efficiently. Consequently, the operator decided to displace the OBM before the wells were lifted.

Various options for displacing the OBM were evaluated. Running washpipe with screens with concentric string rotation was not feasible and would have increased the weight of the completion string, increasing drag. In these long wells, the heavy washpipe would also have tested the tensile limits of the service tool and made it difficult to run the screens to TD. Coiled tubing was not available, and running washpipe along the openhole section in a separate trip would take too long. The operator asked SLB to find an alternative method to displace the OBM.

ResFlow check-valve ICDs eliminated need for washpipe

SLB recommended its ResFlow check-valve ICDs, which dispense with the need for washpipe. Comprising a ball, plate, and ceramic nozzle, the ICD prevents fluid loss through the nozzle during washdown and then controls the flow of hydrocarbons during production like a standard ResFlow ICD.

Screens equipped with the ICDs were run in hole. Subsequently, the pressure of the fluid pumped down the completion string caused the ball in each ICD to close the corresponding check valve and prevent fluid from leaking into the annulus through the nozzle. The fluid traveled the length of the completion string to the toe of the well and then back up the annulus. When pumping stopped, the balls fell back and the check-valve ICDs behaved like standard ResFlow ICDs, helping balance inflow along the wellbore.

Operation trimmed 2 days and saved up to USD 2 million per well

Eliminating deployment of washpipe saved the operator significant rig time and opex.